Waist-to-neck ratio and TG/HDL-C ratio as predictors of insulin resistance in non-diabetic adults with overweight/obesity: A cross-sectional study

Background: Simple anthropometric ratios and lipid-based indices may help identify insulin resistance (IR) in routine practice, especially where clamp techniques are not feasible. We evaluated anthropometric ratios—including waist-to-neck ratio (WNR) and waist-to-height ratio (WHtR)—and the triglyceride-to-high-density lipoprotein cholesterol (TG/HDL-C) ratio as potential predictors of IR in non-diabetic adults with overweight/obesity. Methods: In this cross-sectional study, 49 non-diabetic adults (age 18–75 years) with body mass index (BMI) ≥ 25 kg/m² were enrolled. Anthropometric measurements (waist, neck, hip, height, and weight) and fasting biochemical parameters were obtained. IR was defined as HOMA-IR ≥ 2.5. Pearson correlations assessed relationships between HOMA-IR and candidate ratios/indices. Variables associated with IR were evaluated using multivariable logistic regression. Results: The mean age was 43.24 ± 11.20 years; 77.6% were female; the mean BMI was 33.80 ± 5.15 kg/m². IR was present in 25/49 participants (51.0%). WNR (r=0.293, p=0.041) and WHtR (r=0.341, p=0.016) correlated positively with HOMA-IR, whereas the neck-to-weight ratio correlated negatively (r=–0.358, p=0.012). The TG/HDL-C ratio correlated positively with HOMA-IR (r=0.344, p=0.015). In multivariable logistic regression, TG/HDL-C (odds ratio (OR) 1.432; 95% CI 1.050–1.953; p=0.023) and WNR (OR 15.469; 95% CI 1.446–165.541; p=0.024) remained independently associated with IR. Conclusions: In non-diabetic adults with overweight/obesity, the TG/HDL-C ratio and WNR were independently associated with IR, supporting their use as accessible screening tools. WHtR and additional exploratory ratios (e.g., neck-to-weight) showed significant correlations with HOMA-IR and may merit further validation in larger cohorts.